J 2017

Gravitational instability of polytropic spheres containing region of trapped null geodesics: a possible explanation of central supermassive black holes in galactic halos

STUCHLÍK, Zdeněk, Jan SCHEE, Bobir TOSHMATOV, Jan HLADÍK, Jan NOVOTNÝ et. al.

Základní údaje

Originální název

Gravitational instability of polytropic spheres containing region of trapped null geodesics: a possible explanation of central supermassive black holes in galactic halos

Autoři

STUCHLÍK, Zdeněk (203 Česká republika, garant, domácí), Jan SCHEE (203 Česká republika, domácí), Bobir TOSHMATOV (860 Uzbekistán, domácí), Jan HLADÍK (203 Česká republika, domácí) a Jan NOVOTNÝ (203 Česká republika, domácí)

Vydání

Journal of Cosmology and Astroparticle Physics, 2017, 1475-7516

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10308 Astronomy

Stát vydavatele

Velká Británie a Severní Irsko

Utajení

není předmětem státního či obchodního tajemství

Kód RIV

RIV/47813059:19240/17:A0000015

Organizace

Filozoficko-přírodovědecká fakulta – Slezská univerzita v Opavě – Repozitář

UT WoS

000408310600026

Klíčová slova anglicky

gravitational waves / theory; star formation; stars

Příznaky

Mezinárodní význam, Recenzováno

Návaznosti

GB14-37086G, projekt VaV.
Změněno: 5. 4. 2018 17:17, Jan Hladík

Anotace

V originále

We study behaviour of gravitational waves in the recently introduced general relativistic polytropic spheres containing a region of trapped null geodesics extended around radius of the stable null circular geodesic that can exist for the polytropic index N > 2.138 and the relativistic parameter, giving ratio of the central pressure p_c to the central energy density rho_c, higher than sigma = 0.677. In the trapping zones of such polytropes, the effective potential of the axial gravitational wave perturbations resembles those related to the ultracompact uniform density objects, giving thus similar long-lived axial gravitational modes. These long-lived linear perturbations are related to the stable circular null geodesic and due to additional non-linear phenomena could lead to conversion of the trapping zone to a black hole. We give in the eikonal limit examples of the long-lived gravitational modes, their oscillatory frequencies and slow damping rates, for the trapping zones of the polytropes with N is an element of (2.138, 4). However, in the trapping polytropes the long-lived damped modes exist only for very large values of the multipole number l > 50, while for smaller values of l the numerical calculations indicate existence of fast growing unstable axial gravitational modes. We demonstrate that for polytropes with N >= 3.78, the trapping region is by many orders smaller than extension of the polytrope, and the mass contained in the trapping zone is about 10^(-3) of the total mass of the polytrope. Therefore, the gravitational instability of such trapping zones could serve as a model explaining creation of central supermassive black holes in galactic halos or galaxy clusters.